Which agent is used to prevent hemorrhagic cystitis when using Cytoxan?

Mesna is specifically used to prevent hemorrhagic cystitis, a potential side effect associated with the use of the chemotherapy drug Cytoxan (cyclophosphamide). Cyclophosphamide is metabolized in the body to toxic metabolites that can irritate the bladder and lead to hemorrhagic cystitis, characterized by bleeding and inflammation of the bladder lining.

Mesna works by binding to these toxic metabolites, specifically acrolein, thereby neutralizing their harmful effects on the bladder. This effectively reduces the incidence of hemorrhagic cystitis in patients receiving Cytoxan treatment. For this reason, mesna is commonly administered alongside Cytoxan as a protective agent.

While hydration therapy is also important in the management of patients receiving cyclophosphamide, as it helps dilute the toxins and promotes their excretion, it does not directly neutralize the toxic metabolites. Thus, while hydration can be a supportive measure, it does not serve the specific role that mesna does in preventing the bladder damage caused by Cytoxan. The other options, 5-FU and Alkeran, are unrelated to the prevention of hemorrhagic cystitis with Cytoxan and do not play a role in this context.